Ignition coil



Aug. 23, 1932. HARTZELL 1,873,122

IGNITION COIL Filed Jan. 8, 1950 Jef/.4

Patented Aug. 23, 1932 UNITED STATES PATENn OFFICE HERMAN L. HARTZELL, F ANDERSON, INDIANA, ASSIGNOR TO DELCO-REMY CORPORA- n* TION, 0F ANDERSON, INDIANA,

A CORPORATION 0F. DELAWARE IGNITION GOIL i Application ledv January 8, 1930. Serial No. 419,352.

This invention relates to the manufacture of ignition coils for use in automotive engineering, though it is adaptable to the manufacture of coils fo`r any of the varied uses to which electrical coils may be applied.

One of the objects of the invention is to provide a coil Winding of simplified structure that is eiicient in its operation and which can be constructed yat relatively low cost.

Another object of the invention is to secure the lead-in wire to a coil assembly in a manner that will assure positive electrical contact between the lead-in wire and coil winding.

Another object of the invention is to provide a coil structure of the class wherein the lead-in wire is less subject to rupture or severance from the electrical connection b- 'tween it and the winding assembly.

A further object of the invention is to improve eleetrical coils in general.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to 25 the accompanying drawing wherein a preferred embodiment of one form of the prescnt invention is clearly shown.

i In the drawings:

Fig. 1 is a longitudinal section through a 30 coil winding assembly illustrating one form of the invention.

Fig. 2 is a cross sectional view through one end of the assembly substantially as indicated by the line and arrows 2-2` of Fig. 1.

Fig. 3 is a plan view of the coil supporting tube and a few turns of the first winding thereon, substantially as indicated by the line and arrows 3-3 of Fig. l, to illustrate. the means and method of anchoring the winding 0 and making electrical engagement with the leadin wire. l i

Fig. 4 is an enlarged View with the details thereof shown in exaggeration so as to better illustrate the features of this invention.

Fig. 5 is a view showing a modified form of the lead-in wire securing means.

With particular reference to the drawing,

2() indicates a nonconducting tube or support upon which windings 21 and 22 of the coil 50 are to be wound. Preparatory to winding the coil assembly the nonconducting tube is l provided with a bared lead-in wire 23 which is secured to the tube 20 by means of a staple 21 passing over an intermediate portion 25 of the lead-in wire 23,V and which pierces the tube 2O to be clinched against the inner surface thereof as at 26 and 27. This leaves the lead-in wire 23 with a short free end 30 and a longer free end 31 for purposes that will presently appear.

It will be noted from the illustration in Figs. 2, 3, 4 and 5, that the stapling of the \lead 23 to the tube 20, is sufficient to rigidly hold the lead 23 to the tube 2O so that it may not readily be separated therefrom by accidental strains or'forces applied to the lead 23. This is due tothe fact that the .stapling of the lead to the tube flattens the lead-in wire considerably at 25, the regionof engagement between the two, so that it is firmly clamped against the body of the tube.

In they process of manufacture it is the practice to provide the tubes with the lead-in wire stapled thereto in great masses. These tubes are then placed upon the winding mandrels in banks or groups so that a number of coils may be Wound at the same time. The instant invention is particularly desirable for this method of manufacture, since the lead-in wires and supporting tubes are of luniform constructon which provide means for uniform construction of the coil as a whole. In 'one form of .the device the staple 24 is arranged at right angles to the axis of the tube 20 and the lead-in wire 23 as `illustrated in Fig. 4, while in other forms it is found desirable to aiix the staple 24 parallel with the axis of the tube 20 substantially as illustrated in Fig. 5. In either instance they essence of the invention is the same. The staple 24 op'- erates to secure the lead-in wire 23 in fixed relation with respect to the tube 20, so that the procedure in attaching the wire of the winding 21 to the lead-in wire and tube is the same in all instances.

. The tubes 20 with their attached lead-in wires 23 being in completed form and mounted upon the mandrel for winding, the

wire of the first winding 21 to be woundy upon the co is bared for a portion of its length as at 35, or in other words the insulation 36 thereof is removed so as to provide a bared end which is wrapped or twisted about the short free end 30 of the lead-in wire'23 as shown in Figs. 3, 4 and 5. After the wire is thus anchored to the lead-in wire, it may be additionally. secured thereto by soldering, if it is so desired. However,when secured,the wire is wound upon the tube substantially as illustrated in Fig. 3, in which there are a few relatively widely spaced turns of wire as 36, and thence with more closely spaced turns as shown at 37, the winding is continued until the first layer thereof about the tube 20, is completed.

The firstlayer of wire being complete the same is wrapped with a number of layers 38 of insulation paper 45, and thence follow subsequent layers of wire and insulation until `the winding 2l is completed, after which a strip of insulating paper 46 as a separator is wrapped about the winding, and thence follow alternate wrappings of wire and paper to make up the winding 22 to the particular specification. About the winding 22 is an insulated wrapping of nonconducting material 47, which completes the winding assembly. Spacing of the first few turns of the winding from the juncture with the leadin wire preclude possible short circuiting be tween the turns which is so destructiveto eiicient coil operation. A short circuit of this nature is not permissible in an ignition coil for the voltage induced in each turn is suicient to cause considerable current to flow through the shorted turns, which short circuit current subtracts from the energy available for the spark, and also because of the reverse ampere turns produced thereby, decreases the rate at which the magnetic flux surrounding the winding decays. Since the voltage of the secondary is proportional to the rate at which the flux decays, any tendency to change this rate will have'very direct effect on the coil.

In addition the short circuit current will produce local heating at this point, which after a time will cause deterioration of insulation and the growth of the short, which will cause the coil to com letely fail.

The added insulation a orded by the successive turns of the paper 45 as at 38 contributes to the individual insulation of the successive turns of the first layer of wire in that the successive layers are amply insulated from the first, and one from the other.

The winding assembly thus "constructed is ready to be mounted within its container and assembled with its cooperating elements in any preferred form. The result produced is a coil assembly -of rigid construction in which the parts are securely ixed together in a way to insure positive electrical and mechanical connection. The lead-in wire 23 cannot readily be withdrawn from the aspresent invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all

kcoming within the scope of the claim which follows.

lVhat is claimed is as follows:

In an electrical coil, the combination comprising,'an insulated support; a lead-in wire secured to said support; and a winding connected conductively to said lead-in wire, said winding comprising a major portion with evenly spaced turns and a minor portion with varyingly spaced turns, the turns of said minor portion wound on said support in regularly decreasing spaced relation from the point of connection with said lead-1n wire to the evenly spaced turns of said major portion, the spacin of the turns in the minor portion being ecreased in proportion to the tendency of short circuiting between successive turns and until the spacing of the minor portion merges into the spacing of the evenly spaced turns of said major portion whereby the tendency of short circuiting between any successive turns is eliminated. t

In testimony whereof I hereto aix my signature.

HERMAN L. HARTZELL. 

